The present invention relates to a data correction method and an X-ray CT (computer tomography) apparatus, and more particularly to a data correction method and an X-ray CT apparatus capable of applying correction adapted to the shape of a subject to be imaged.
There is known a conventional X-ray CT apparatus for: if data has a larger value than an upper threshold, applying smoothing to the data; if data has a smaller value than a lower threshold, taking the data as is; and if data has a value between the upper and lower thresholds, applying smoothing to the data, the degree of which smoothing is lower than that for the data of a larger value than the upper threshold, and becomes higher in proportion as the data has a larger value (for example, see Patent Document 1).
[Patent Document 1] Japanese Patent Application Laid Open No. 2000-5159.
In such a conventional X-ray CT apparatus, the degree of correction processing is changed simply according to the magnitude of data.
However, assuming that the shape of a subject to be imaged is so complex as to make one of data elements adjacent to each other in the view or channel direction have a larger value and the other have a smaller value, the technique as described above causes the degree of smoothing to be increased for one of the adjacent data elements and decreased for the other, which is unreasonable. That is, the conventional X-ray CT apparatus poses a problem that correction adapted to the shape of the subject to be imaged can sometimes not be applied.